Sulphonyl isocyanates, addition

The cyclic addition of sulphonyl isocyanates to S4N4 has been shown. The monoaddition product (27) is formed without exception and is explained by... 

In a related piece of work, imidazolines have been prepared from A -chloro-N-phenyl amidines and enamines. (Scheme 79). Pyrazomycins have been synthesized by the Roche group, the key step being the preparation of the pyrazolone ring by the addition of toluene- -sulphonyl azide to the anion from diethyl acetone dicarboxylate (Scheme 80). Imidazolidines (201) have been prepared by the action of isocyanates and isothiocyanates with an aziridine ester a dipolar intermediate is implicated. Imidazolidine-4,5-diones have been prepared by the... 

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